Solved: Outline the process of spermatogenesis in the human testis. Compare and contrast... [IB Biology]

Similarities:

Both involve mitosis to produce precursor cells. 1 mark
Both involve meiosis to produce haploid gametes. 1 mark
Both involve cell differentiation to produce mature gametes. 1 mark Differences:
Spermatogenesis produces four haploid sperm per meiosis, while oogenesis produces one haploid ovum and three polar bodies. 1 mark
Spermatogenesis is continuous from puberty onwards, while oogenesis has long pauses (e.g., meiosis I starts before birth, meiosis II completes only at fertilization). 1 mark
Spermatogenesis occurs in the testes, while oogenesis occurs in the ovaries. 1 mark
Millions of sperm are produced daily, whereas only one egg is released per menstrual cycle. 1 mark

The placenta facilitates the exchange of nutrients (e.g., glucose, amino acids) from the mother's blood to the fetus. 1 mark
It allows for the exchange of waste products (e.g., carbon dioxide and urea) from the fetus to the mother. 1 mark
The placenta produces hormones, including human chorionic gonadotropin (hCG), which maintains the corpus luteum and progesterone production. 1 mark
Later in pregnancy, the placenta secretes progesterone and estrogen to maintain the uterine lining and prevent contractions. 1 mark
It acts as a barrier to some pathogens (though not all, e.g., some viruses like rubella can cross the placenta). 1 mark
It provides oxygen to the fetus via diffusion. 1 mark
It has chorionic villi to increase surface area for efficient exchange of substances. 1 mark
The placenta prevents maternal and fetal blood from mixing, which is important due to possible differences in blood types. 1 mark
The umbilical cord connects the fetus to the placenta, containing two arteries and one vein to facilitate blood transport. 1 mark

Biology International Baccalaureate (IB) Practice Question: 1. Outline the process of spermatogenesis in the human testis. 2. Compare and contrast spermatogenesis and oogenesis....